Circuit control



Sept, 19, 1939. R. E. BRESSLER 2,173,157

CIRCUIT CONTROL Filed March 15, 1937 Patented Sept. 19 1939 UNITED STATES PATENT OFFICE CIRCUIT CONTROL of Illinois Application March 15, 1937, Serial No. 130,967

1 Claim.

This invention relates to improvements in circuit controls and it consists of the matters hereinafter described and more particularly pointed out in the appended claim.

In circuit controls, including relatively movable contacts wherein a fuse member is employed in circuit with one of the contacts, when the contacts for any reason do not break as intended, the fuse member burns out and requires renewal in order to reestablish the circuit. At times the contacts adhere and fuse together as a result of a short circuit or other abnormal condition. Again, freezing or adherence of the contacts may be caused by a sudden severe overload, such as a short circuiting of wires between the relay and motor or other electrical device controlled by the relay. Attempts to renew the fuse, without separating the contacts, is not only dangerous to the one making the renewal, but considerable damage is possible to mechanisms with which the circuit is associated.

One of the objects of the present invention is to provide a circuit control in which the contacts must be manually or otherwise separated before it is possible to renew the burned out fuse.

A further object of the invention is to provide a circuit control of this kind which is simple in construction, is positive in operation, may be produced at a relatively low cost and is adapted for use in connection with many different kinds of mechanisms involving the engagement and disengagement of relatively movable contacts in a circuit.

Another object of the invention is to provide a circuit control which is especially adapted for use in the smaller electrical instruments or devices, such as relays, automatic switches and the like and which adds substantially to the efficiency thereof without adding appreciably to the cost of manufacture.

The above mentioned objects of the invention, as well as others, together with the advantages thereof, will more fully appear as I proceed with my specification.

In the drawing:

Fig. 1 is a view in front elevation of a circuit control, such as a relay, embodying one form of the invention.

Fig. 2 is a view in side elevation of the relay shown in Fig. 1 when the associated contacts thereof are normally disengaged and the circuit controlled thereby is open or broken.

Fig. 3 is a view similar to Fig. 2 when the associated contacts are engaged to close the circuit in which they are employed.

Fig. 4 is a perspective view of a fusible link which may be advantageously employed in the circuit control.

Fig. 5 is a view partly in side elevation and partly in vertical section showing the improved circuit control embodied in a water level alarm or the like.

Referring now in detail to that embodiment g of the invention illustrated in Figs. 1, 2 and 3 of the accompanying drawing: I0 indicates a relay frame to which a coil II is secured with its axis arranged at a right angle to one face of the frame. l2 indicates a member also fixed to the frame above the coil and forming a fixed support for a contact I3. A bracket 14 is secured to the frame and this bracket is provided with an extension [5 arranged below the coil. [6 indicates the armature of the relay which is pivoted as at I! to the front end of the extension I5. This armature has a right angle tail piece arranged beneath the extension l5 and adapted to engage a part of the same to limit the swinging or pivotal movement of the armature away from the coil.

The armature is provided with a contact carrier plate 18 having a yieldable pivotal connection [9 with the armature whereby said plate may be swung away from the armature as indicated in dotted lines in Fig. 2. A spring 20 connects the bottom end of the carrier plate with the frame so as to return the plate and the armature to the open position, as shown in full lines 351 in Fig. 2 when the associated coil II is deenergized.

A piece of insulation 2! is secured to the inner face of the top end of the carrier plateas by' a rivet 22. A fusible link 23, such asshown in perspective in Fig. 4, is SBCUIQQQ tO; the, inner face of the insulation piece follows: A bind-- ing post 24 extends through the piece 2| and. through a slot 23a in the link from the inner face of the said piece and a nut 25 is threaded on the outer end of said post in a manner to retain one end of a conductor 26 forming a part of the circuit controlled.

A contact post 21 extends through an opening 23b in the fusible member and through the top end of the insulation piece 21. The inner end of the post 21 is made as a contact 28 adapted to be engaged with and disengaged from the fixed contact l3. A nut 29 is threaded on the outer end of the post 21 to secure the parts in place.

When the coil II is deenergized, the armature l6 and the parts carried thereby stand in the open position, as shown in full lines in Fig. 2. When the coil H is energized, it attracts the armature and causes the same to swing clockwise as appears in Figs. 1 and 2 into a position wherein the movable contact 28 engages the fixed contact 13. As the contact is in circuit with a conductor 2611, this closes the electrical connection between the two conductors 26-26a through the contacts [3 and 28 and the fusible link 23.

Should a short occur in the circuit thus established, the fusible link will burn through and break the circuit. In certain instances, as a result of a short or other abnormal condition, the contacts l3 and 28 may seize, adhere or stick together. It is apparent that with the structure described, before it is possible to renew the fusible link, the contacts l3 and 28 must first be separated before access is had to the burned out link, for renewal.

With the present invention, after the contacts have been separated, in any suitable manner, the carrier plate l8 with the insulation piece 2| thereon may be swung outwardly and away from the armature about the yielding pivotal connection 89 therewith, into the dotted line position shown in Fig. 1. When the nuts 29 on the posts 2 i2l are removed, the posts may be withdrawn from the inner side of the insulation piece so that the fragments of the burned out fusible link may be removed. Thereafter, a new link is substituted for the burned out one, the posts 24-21 are then replaced and the nuts 2529 threaded thereon. With the fusible link replaced, the carrier is released and snaps back into normal relation with respect to the armature, as shown in full lines in Fig. 2.

In Fig. 5, the invention is illustrated as embodied in a water level alarm which includes a casing 35 in a pipe line 3i. A float arm 32 is fixed on a shaft 33 journalled in the casing as shown with one end projecting beyond one side of the casing. A fuse carrier arm 2la of insulation is fixed to the end portion of the shaft 33 outside the casing. A fusible link 2331 similar to the link 23 before mentioned, is secured to one face of the carrier by the binding posts 21a24a and associated nuts 25a-29a as shown. The post 21a has a head providing a contact 28a which is adapted to engage with and be disengaged from the fixed contact I301, on the support l2a.

Freezing or adhering of the contacts l3 and 28 may be caused by a sudden severe overload such as a short circuiting of the wires between the relay and the motor or other electrical device controlled by the relay.

In the operation of the device, should the contacts I311 and 28a respectively adhere together and a short circuit cause a burning out of the link 23:12, the contacts I3a and 28a must be separated before it is possible to renew or replace the link.

The improved control makes separation of the adhered contacts imperative before it is possible to renew a burned out fuse. This provides a safety factor, not only for the person making the fuse change, but for the circuit being controlled. The improved control is simple in construction and adds substantially nothing to the cost of the device in which it is embodied for its intended purpose.

While in describing the invention, I have referred in detail to the form, arrangement and construction of the parts involved, the same is to be considered only in its illustrative sense so that I do not wish to be limited thereto except may be specifically set forth in the appended claim.

I claim as my invention:

In a circuit control, a relay embodying therein a fixed contact, a magnetic coil, a pivotally mounted armature adapted for attraction by said coil, an arm of insulating material carried by and movable with said armature, a contact carried by said insulating arm, means for attaching a conductor to said arm, and a fuse carried by said arm for electrically connecting said contact carriedby said arm and said attaching means,said fuse being arranged on that side of said arm facing the fixed contact and being renewable only when said contact carried by said insulating arm is out of engagement with the fixed contact.

ROBERT E. BRESSLER. 

